YUANNENGJI LEDとは?
LEDは英語で発光ダイオードです。, 半導体固体発光素子です. 発光材料として固体半導体チップを使用. 両端に順方向電圧を印加した場合, 半導体内のキャリアが再結合して光子放出を引き起こし、光を生成します. LEDは赤色を直接発光可能, 黄色, 青, 緑, シアン, オレンジ, 紫, そして白い光. 最初の商用ダイオードが製造されたのは、 1960. その基本構造はエレクトロルミネセンス半導体材料です。, リード付きのラックに置かれる, 内部芯線を保護するために周囲をエポキシ樹脂で封止, LEDは耐震性に優れています. 2. LEDが第4世代光源である理由 (緑色の照明 )?
電気光源の発光機構による分類:
第一世代の光源: 白熱灯などの抵抗発光.
第二世代光源: ナトリウムランプなどのアーク発光やガス発光.
第三世代光源: 蛍光灯などの蛍光体発光体.
第4世代光源: LEDなどの固体チップ発光.
LEDの発光メカニズムと動作原理は何ですか?
発光ダイオードはIII-IV族化合物から作られています, GaAsなど (ガリウムヒ素), ギャップ (リン化ガリウム), GaAsP (ガリウムヒ素リン化物) その他の半導体, そしてそれらのコアはPN接合です. したがって, 一般的なP-N接合のI-N特性を持ちます。, つまり, 順伝導, リバースカットオフ, および破壊特性. さらに, 特定の条件下で, 発光特性もあります. 順電圧不足, 電子がN領域からP領域に注入される, 正孔が P 領域から N 領域に注入されます。. 少数キャリアの一部 (少数キャリア) 他の領域に入ったものは多数キャリアと再結合する (マジョリティキャリア) 光を発する.
LEDの光学特性とは何ですか?
(1) LEDが発する光は単色でも広帯域でもない, しかし、両者のバランス.
(2) LED 光源は点光源に似ていますが、点光源ではありません。.
(3) LEDが発する光の色は空間方向によって異なります.
(4) 定電流動作時の LED のジャンクション温度は順電圧 VF に大きな影響を与えます。.
LEDを構築するさまざまな方法は何ですか?
LED は色が異なるため、化学組成が異なります。:
例えば, 赤: アルミニウム、インジウム、ガリウム、リン化物
緑と青: 窒化インジウムガリウム
白などの色はRGBの三原色を適切な割合で混ぜ合わせて作られます。. LEDの製造プロセスは半導体の製造プロセスと似ています, ただし加工精度は半導体ほどではない, 現在のコストはまだ比較的高い.
さまざまな色の波長は何ですか?
中国で一般的に使用されているいくつかの超高輝度 LED のスペクトル波長分布は 460 ～ 636nm です。, そして波長は青です, 緑, 黄緑色, 黄色, 黄オレンジ, 短いものから長いものまで赤. いくつかの一般的なカラー LED の典型的なピーク波長は次のとおりです。:
青 – 470nm,
青緑 – 505nm,
緑 – 525nm,
黄色 – 590nm,
オレンジ – 615nm,
赤 – 625nm.
LEDのパッケージング方法は何ですか?
梱包方法:
(1) ピンタイプ (ランプ) LEDのパッケージング,
(2) 表面実装 (SMD) タイプ ( SMT-LED) 梱包,
(3) チップオンボード (COB) 導かれた 梱包,
(4) システムインパック (SiP) LEDのパッケージング
(5) ウェーハボンディングとチップボンディング.
LEDの分類方法は何ですか?
1. 発光管の色に合わせて
発光管の色に合わせて, 赤に分けることができます, オレンジ, 緑 (さらに黄緑に細分化される, スタンダードグリーンとピュアグリーン), ブルーライト, 等. さらに, 一部の発光ダイオードには 2 色または 3 色のチップが含まれています.
発光ダイオードに散乱剤がドープされているかどうかによる, そしてそれが有色か無色か, 上記のさまざまな色の発光ダイオードも4つのタイプに分類できます: 色付き透明, 無色透明, 有色散乱と無色散乱. 散乱型発光ダイオードで表示灯として使用されます。.
2. 発光管の発光面の特性に応じて
発光管の発光面の特性に応じて, 丸いランプに分割できます, 正方形のランプ, 長方形ランプ, 面発光管, 側管, 表面実装型マイクロチューブ, 等. 円形ランプはφ2mmに分類されます, φ4.4mm, φ5mm, φ8mm, 直径に応じてφ10mmとφ20mm. 外国では, φ3mm LEDは通常T-1と表記されます。; T-1としてφ5mm(3/4); T-1と同様にφ4.4mm(1/4). 半値角は、円形の光度の角度分布を推定するために使用できます。. 光度の角度分布に基づいて3つのタイプがあります:
(1) 高い指向性. 一般的に, それは尖ったエポキシパッケージまたは金属反射キャビティを備えたパッケージです, 散乱剤は添加されていません. 半値角は5°～20°以下, 指向性が高い. 局所照明として使用可能, または光検出器と組み合わせて使用して自動検出システムを形成します.
(2) 標準タイプ. 通常は表示灯として使用されます, its half-value angle is 20°～45°.
(3) Scattering type. This is an indicator light with a larger viewing angle, a half-value angle of 45°～90° or more, and a larger amount of scattering agent.
3. According to the structure of the light-emitting diode
According to the structure of the light-emitting diode, there are full epoxy encapsulation, metal base epoxy encapsulation, ceramic base epoxy encapsulation and glass encapsulation.
4. According to the luminous intensity and working current
According to the luminous intensity and working current, there are ordinary brightness LEDs (luminous intensity>10マクド); ultra-high brightness LEDs (luminous intensity<100マクド); the luminous intensity between 10 and 100mcd is called High brightness light emitting diode. The working current of general LED is between tens of mA and tens of mA, while the working current of low current LED is below 2 mA (the brightness is the same as that of ordinary light emitting tube).
In addition to the above classification methods, there are also classification methods by chip material and by function.
LEDの製造工程はどのようなものですか?
1. Process:
ある) Cleaning: Use ultrasonic cleaning of PCB or LED bracket and drying.
b) Mounting: Prepare silver glue on the bottom electrode of LED tube core (large wafer) and expand it. Place the expanded tube core (large wafer) on the crystal table. Use a crystal pen to install the tube core one by one on the corresponding pad of PCB or LED bracket under a microscope, and then sinter to solidify the silver glue.
c) Pressure welding: Use aluminum wire or gold wire welding machine to connect the electrode to the LED tube core as a lead for current injection. LED is directly mounted on PCB, generally using aluminum wire welding machine. (Gold wire welding machine is needed to make white light TOP-LED)
d) Packaging: Use epoxy to protect LED core and welding wire through dispensing. Dispensing on PCB board has strict requirements on the shape of colloid after curing, which is directly related to the brightness of the finished backlight source. This process will also undertake the task of dispensing phosphor (white light LED).
e) Welding: If the backlight source is SMD-LED or other packaged LED, the LED needs to be welded to the PCB board before the assembly process.
f) Film cutting: Use punching machine to die-cut various diffusion films, reflective films, 等. required for the backlight source.
g) Assembly: According to the requirements of the drawing, manually install various materials of the backlight source in the correct position.
h) Testing: Check whether the photoelectric parameters and light uniformity of the backlight source are good.
2. The task of LED packaging
is to connect the external lead to the electrode of the LED chip, protect the LED chip at the same time, and play a role in improving the light extraction efficiency. The key processes are mounting, pressing and packaging.
3. LED packaging Form
LED packaging forms can be said to be varied, mainly according to different application scenarios with corresponding external dimensions, heat dissipation measures and light output effects. LEDs are classified into Lamp-LED, TOP-LED, Side-LED, SMD-LED, High-Power-LED, 等. according to packaging forms.
4. LED packaging process flow
5. Packaging process description
(1). Chip inspection
Microscopic inspection: whether there is mechanical damage and pits (lockhill) on the surface of the material, whether the chip size and electrode size meet the process requirements, and whether the electrode pattern is complete.
(2). Chip expansion
Since LED chips are still closely arranged and the spacing is very small (about 0.1mm) after dicing, it is not conducive to the operation of the subsequent process. We use a film expander to expand the film of the bonded chip, so that the spacing of the LED chip is stretched to about 0.6mm. Manual expansion can also be used, but it is easy to cause problems such as chip falling and waste.
(3). Glue dispensing
Apply silver glue or insulating glue to the corresponding position of the LED bracket. (For GaAs and SiC conductive substrates, 赤, 黄色, and yellow-green chips with back electrodes, silver glue is used. For blue and green LED chips with sapphire insulating substrates, insulating glue is used to fix the chips.) The difficulty of the process lies in the control of the amount of glue dispensing. There are detailed process requirements for the height of the colloid and the location of the glue dispensing. Since silver glue and insulating glue have strict requirements for storage and use, the waking up, stirring, and use time of silver glue are all matters that must be paid attention to in the process.
(4). Glue preparation
In contrast to glue dispensing, glue preparation is to use a glue preparation machine to first apply silver glue to the back electrode of the LED, and then install the LED with silver glue on the back on the LED bracket. The efficiency of glue preparation is far Higher than glue dispensing, but not all products are suitable for glue preparation process.
(5). Manual pricking
Place the expanded LED chip (with or without glue) on the fixture of the pricking table, put the LED bracket under the fixture, and use a needle to pierce the LED chips one by one to the corresponding position under a microscope. Compared with automatic mounting, manual pricking has an advantage that it is easy to replace different chips at any time, which is suitable for products that need to install multiple chips.
(6). Automatic mounting
Automatic mounting actually combines the two steps of glue dispensing and chip installation. 初め, silver glue (insulating glue) is applied to the LED bracket, and then the LED chip is sucked up and moved to the position with a vacuum nozzle, and then placed in the corresponding bracket position. The main process of automatic mounting is to be familiar with the equipment operation programming, and at the same time adjust the glue dispensing and installation accuracy of the equipment. When choosing the nozzle, try to use bakelite nozzles to prevent damage to the surface of the LED chip, especially blue and green chips must be made of bakelite. Because the steel nozzle will scratch the current diffusion layer on the surface of the chip.
(7). Sintering
The purpose of sintering is to solidify the silver glue. Sintering requires temperature monitoring to prevent batch defects. The temperature of silver glue sintering is generally controlled at 150℃ and the sintering time is 2 時間. According to actual conditions, it can be adjusted to 170℃ for 1 時間. The insulating glue is generally 150℃ for 1 時間. The silver glue sintering oven must be opened every 2 時間 (または 1 時間) to replace the sintered product according to the process requirements. It must not be opened at will in the middle. The sintering oven must not be used for other purposes to prevent pollution.
(8). Press welding
The purpose of press welding is to lead the electrode to the LED chip and complete the connection of the internal and external leads of the product. There are two types of LED press welding processes: gold wire ball welding and aluminum wire press welding. The right picture shows the process of aluminum wire press welding. 初め, press the first point on the LED chip electrode, then pull the aluminum wire to the top of the corresponding bracket, press the second point and then break the aluminum wire. In the process of gold wire ball welding, a ball is burned before pressing the first point, and the rest of the process is similar. Pressure welding is a key link in LED packaging technology. The main things that need to be monitored in the process are the arch shape of the gold wire (aluminum wire), the shape of the solder joint, and the tension. In-depth research on the pressure welding process involves many aspects, such as gold (アルミニウム) wire material, ultrasonic power, pressure welding pressure, selection of splitter (steel nozzle), movement trajectory of splitter (steel nozzle), 等. (The figure below is a microscopic photo of the solder joints pressed by two different splitters under the same conditions. There are differences in the microstructure of the two, which affects the product quality.) We will not repeat it here.
(9). Glue dispensing LED packaging mainly includes glue dispensing, potting, and molding. Basically, the difficulties in process control are bubbles, multiple missing materials, and black spots. The design mainly focuses on the selection of materials and the selection of epoxy and brackets with good combination. (General LEDs cannot pass the airtightness test) As shown in the right figure, TOP-LED and Side-LED are suitable for glue dispensing. Manual dispensing packaging requires a high level of operation (especially for white light LEDs). The main difficulty is to control the amount of dispensing, because the epoxy will thicken during use. The dispensing of white light LEDs also has the problem of phosphor precipitation causing light color difference.
(10). Glue encapsulation
Lamp-LED encapsulation adopts the form of encapsulation. The encapsulation process is to first inject liquid epoxy into the LED molding cavity, then insert the pressed LED bracket, put it in an oven to let the epoxy solidify, and then remove the LED from the cavity to form it.
(11). Molded packaging
Put the pressed LED bracket in Put it into the mold, close the upper and lower molds with a hydraulic press and evacuate them.
Put the solid epoxy into the entrance of the injection channel, heat it, and press it into the mold channel with a hydraulic push rod. The epoxy enters each LED molding groove along the channel and solidifies.
(12). Curing and post-curing
Curing refers to the curing of the encapsulated epoxy. The general epoxy curing conditions are 135℃ for 1 時間. The molded package is generally at 150℃ for 4 minutes.
(13). Post-curing
The purpose of curing is to fully cure the epoxy and thermally age the LED. Post-curing is very important for improving the bonding strength between the epoxy and the bracket (プリント基板). The general conditions are 120℃ for 4 時間.
(14). Cutting and dicing
Since LEDs are connected together (not individually) during production, Lamp encapsulated LEDs use cutting to cut off the connecting ribs of the LED bracket. SMD-LED is on a PCB board, and a dicing machine is needed to complete the separation work. (15). Testing
Test the photoelectric parameters of LED, check the external dimensions, and sort the LED products according to customer requirements.
(16). Packaging
Count and package the finished products. Ultra-bright LEDs require anti-static packaging.